Method and apparatus to prevent the unauthorized copying of digital information

ABSTRACT

A method for authorizing the rendering of a digital recording. A first section and a last section of a track is first identified. A watermark is then decoded from the first and last sections of the track. It is then determined if at least one reserved bit is marked in the watermark in each of the first and last sections of the track. If so, it is determined if the sequence IDs of sections interposed between the first and last sections of the track are in sequential order. If both conditions are met, the rendering is authorized.

FIELD OF THE INVENTION

[0001] This invention relates primarily to the field of consumerelectronics, and in particular to the protection of copy-protectedcontent material.

BACKGROUND OF THE INVENTION

[0002] Generally, optical discs and other digital storage media arewidely used throughout the world because of their capacity to store andread information. In an optical disc, such as a compact disc (CD), adigital information signal is recorded on one surface and the recordedinformation is reproduced using a laser beam to pick up the digitalsignal.

[0003] The technology associated with the CD has been expanded to coverother areas such as storing digitized audio, video and alphanumericinformation for a variety of purposes, conforming to a number ofstandards such as digital video disc (DVD), CD-ROM (read only memory),MP3 (Motion Picture Experts Group, Audio Layer 3), etc. (Althoughreference is generally made to CDs, it is understood that thedescription and invention generally applies to any optical disc.)

[0004] With regard to MP3, the MP3 format for storing and transmittingcompressed audio files has made the wide-scale distribution of audiorecordings feasible, because a 30 or 40 megabyte digital audio recordingof a song can be compressed into a 3 or 4 megabyte MP3 file. Using atypical 56 kbps dial-up connection to the Internet, this MP3 file can bedownloaded to a user's computer in a few minutes. Thus, an unauthorizedmalicious party may read songs from an original and legitimate CD,encode the songs into MP3 format, and place the MP3 encoded song on theInternet for wide-scale illegitimate distribution. Alternatively, theunauthorized malicious party could provide a direct dial-in service fordownloading the MP3 encoded song. The illicit copy of the MP3 encodedsong can be subsequently rendered by audio playback devices, or can, forexample, be decompressed and stored onto a recordable CD for playback ona conventional CD player.

[0005] A group by the name of Secured Digital Music Initiative (SDMI)has been established by record companies to protect music companies'copyrights on the Internet by providing disc forgery preventiontechniques. SDMI was also founded by the Recording Industry Associationof America (RIAA); the initiative has the support of major labels suchas Universal, EMI, Sony and Time Warner.

[0006] The Secure Digital Music Initiative (SDMI) and others advocatethe use of “Digital Watermarks” to identify authorized content material.As in its paper watermark counterpart, a digital watermark is embeddedin the content material so as to be detectable, but unobtrusive. Anaudio playback of a digital music recording containing a watermark, forexample, will be substantially indistinguishable from a playback of thesame recording without the watermark. A watermark detection device,however, is able to distinguish these two recordings based on thepresence or absence of the watermark.

[0007] An accurate reproduction of watermarked material will cause thewatermark to be reproduced in the copy of the watermarked material. Aninaccurate, or lossy reproduction of watermarked material, however, maynot provide a reproduction of the watermark in the lossy copy of thematerial. A number of protection schemes, including those of the SDMI,have taken advantage of this characteristic of lossy reproduction todistinguish legitimate material from illegitimate material, based on thepresence or absence of an appropriate watermark. In the SDMI scenario,two types of watermarks are defined: “robust” watermarks, and “fragile”watermarks. A robust watermark is one that is expected to survive alossy reproduction that is designed to retain a substantial portion ofthe original content material, such as an MP3 encoding of an audiorecording. That is, if the reproduction retains sufficient informationto allow a reasonable rendering of the original recording, the robustwatermark will also be retained. A fragile watermark, on the other hand,is one that is expected to be corrupted by a lossy reproduction or otherillicit tampering.

[0008] In the SDMI scheme, the presence of a robust watermark indicatesthat the content material is copy protected, and the absence orcorruption of a corresponding fragile watermark when a robust watermarkis present indicates that the copy protected material has been tamperedwith in some manner. An SDMI compliant device is configured to refuse torender watermarked material with a corrupted or absent fragilewatermark, except if the corruption or absence is justified by an“SDMI-certified” process, such as an SDMI compression of copy protectedmaterial for use on a portable player. For ease of reference andunderstanding, the term “render” is used herein to include anyprocessing or transferring of the content material, such as playing,recording, converting, validating, storing, loading and the like.

[0009] An SDMI-compliant device has been envisioned that allows an ownerof a digital recording, such as a CD, to make only four digital copies,based on detected robust and fragile watermarks, of an original CD percopying session. In addition, the SDMI-compliant device does not allow acopy of the CD to be re-copied, if there is an absence or corruption ofa fragile watermark when a robust watermark is present. Further, afterthe four digital recordings of the original CD (or songs containedthereon) has been met, the SDMI-compliant device will allow a user tocopy a section of a track from the original CD of approximately 15seconds or less. The 15 seconds section of a track may be imported,recorded onto a recordable CD, transmitted over the Internet in the formof an MP3 file, etc.

[0010] However, by allowing such a sampling section to be recorded evenafter the recording limit was reached, the potential for avoiding the 4song-recording minimum was opened. For example, a song could be importedin 15-second sections, each section individually identified as aseparate song or track and including a TOC (Table of Contents). Eachsection would then be imported and rendered as a sequence of 15 second“songs”, thus piecing together the original song.

SUMMARY OF THE INVENTION

[0011] To prevent the scenario of piecing together a song with sequencesof track sections re-cast as separate “song”, one approach would be thatthe SDMI compliant device insert, for example, a 2 second gap betweeneach imported song. Thus, if the original song or track is piecedtogether from imported 15-second sections, a 2 second gap will occur inevery 15 seconds of the song. This effectively prevents suchillegitimate copying of songs. Such a system is described in U.S. patentapplication Ser. No. 09/747,513, entitled “System and Method ForInserting Disruptions Into Merged Digital Recordings” for Laszlo Hars,filed Dec. 20, 2000 (Attorney Docket US000401), the contents of whichare hereby incorporated by reference.

[0012] While the insertion of a 2 second gap is an effective solution toprevent such illegitimate importation, a potential drawback exists incertain instances where the user may be making legitimate copies (forexample, making one of the four allowed copies). In many instances, suchas live performances recorded on a CD, the music continues from onetrack to the next without any time gap. As a particular example, on alive CD by the Grateful Dead, the song “China Cat Sunflower” may segueseamlessly into “I Know You Rider”, even though they are identified onthe CD as separate tracks. However, a user who is making an authorizedrecording of the CD would have a 2 second gap inserted between the twotracks. The gap may thus alter the authorized recorded version of the CDfor the user.

[0013] Therefore, there also exists a need for an apparatus and a methodthat may be used to prevent a medium from being copied a certain numberof times and does not force a user who has legally recorded tracks tolisten to gaps in a medium. It is also desirable that the apparatus andmethod be compatible with SDMI and like standards. For example, inaddition to being used in preventing in excess of a number ofrecordings, it is desirable that sections of the medium of up to apre-determined number of seconds, for example, 15 seconds may beimported, rendered and recorded even if the number of authorizedrecordings has already been met.

[0014] Therefore, the focus of the invention is to provide a system thatprevents the unauthorized importing of digital audio recording withoutinserting a time gap between songs.

[0015] It is a further object of the present invention to provide amethod and system that allows a segment of a track on the order of, forexample, 15 seconds, to be imported even if the number of authorizedcopies of the medium or track have been met.

[0016] It is yet a further object of the invention to provide a systemand apparatus that performs the above in compliance with the SDMIprotocol.

[0017] To achieve the above objects, there is a system for producing anoriginal recorded medium that provides a watermark having special bitsincorporated therein. The special bits are incorporated in the watermarkso that at least one special bit is marked in a first section of thetrack and the last section of the track for each track or song of themedium or other original recording. The invention also includes a mediumor other original recording having a watermark that includes the specialbits as so positioned.

[0018] The invention also includes a system or device that records orrenders data originating from a medium or other original recording or atrack of a medium or other original recording by first determining wherea first and last section of the track, having a watermark, are located;decoding the watermark from the track; determining whether at least onespecial bit is marked in the first and last sections of each track; andalso determining whether the interposed sequence IDs in the track havethe proper order between the first and last sections of the track. Ifnot, then recording or rendering is prevented.

[0019] The recording or rendering device or system allows authorizedcopying or rendering of an authorized copy, prevents piecing together asong using smaller sections, and does not insert an artificial gapbetween tracks in order to do so. It is also compatible with the SDMIprotocol. If a track is authorized to be rendered, then the at least onespecial bit will be detected in the first and last sections of the trackand the interposed sequence IDs will be in order. Thus, the renderingwill be authorized.

[0020] If, on the other hand, the rendering is not authorized (forexample, the limit has been exceeded as evidenced by a corruption offragile watermarks in a number of sections of the song), and a userattempts to record or render a song using 15-second sections masked as“songs” (i.e., each having an associated TOC), then the at least onespecial bit will not be found in the first and last sections of thetrack or song. Nor will it find the correct sequence IDs interposedbetween the first and last sections of the track. Thus, there is no needfor a 2 second gap imposed between tracks to prevent unauthorizedcopying, because the recording is denied before any importation orrecording even occurs.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other objects, features, and advantages of thepresent invention will become more apparent in light of the followingdetailed description of an exemplary embodiment thereof taken inconjunction with the attached drawings in which:

[0022]FIG. 1 illustrates a block diagram of a system in accordance withone embodiment of the present invention;

[0023]FIG. 2 illustrates a data portion of an audio recording inaccordance with one embodiment of the present invention; and

[0024]FIG. 3 illustrates a flow-chart of the process for protecting anaudio recording in accordance with one embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0025] Turning now to the drawings, in which like reference numeralsidentify similar elements throughout the several views, and commonlyknown components and functions are omitted to avoid obscuring theinvention.

[0026]FIG. 1 illustrates an example block diagram of a protection system100 in accordance with this invention. The protection system 100comprises an encoder 110 that encodes content material onto a medium130, and a decoder 120 that renders the content material from the medium130 and is discussed in greater detail in copending U.S. applicationSer. No. 09/536,944 entitled, “Protecting Content from IllicitReproduction by Proof of Existence of a Complete Data Set viaSelf-Referencing Sections”, filed on Mar. 28, 2000 for Inventors MichaelA. Epstein, Antonius A. M. Staring and Martin Rosner, the contents ofwhich are hereby incorporated by reference.

[0027] Encoder 110 receives music data of a content source to reader orselector 112. A binder 116 extracts portions of the content data fromreader and attaches a watermark thereto. The term “watermark” referredto in this application is defined as a robust, watermark, fragilewatermark or any type of watermark that can be rendered, stored andrecorded by a CD reader or optical disc device. The watermark is mixedwith the content data (in this case, an audio signal) to provide adecodable and identifiable data structure, such as that shown in FIG.2.The watermark data is provided so that it does not effect the audioquality of the content material. Encoder 110 includes a recorder 114that records the content material from the reader 112 and the contentmaterial and watermark from the binder 116 onto the medium 130.

[0028] Referring to FIG. 2, there is an illustration of a track thatincludes a representation of a recorded data structure, such as thatrecorded by recorder 114 onto medium 130, of FIG. 1, in accordance withthe present invention. Data is stored in the form of a track 201, whichmay represent, for example, one song recorded on a CD. The recorded dataon the track 201 comprises watermark data 201a and music data 201 b.Although the watermark data 201 a and music data 201 b are depictedseparately in FIG. 2, it is understood that these data items are mixed(for example, by binder 116 and recorder 114 of FIG. 1) and storedtogether on the track in digital format. As noted, the watermark data201 a does not interfere with the audio playback, and may be extractedfrom the track (via a decoder for example) to provide for authenticationdiscussed below. Those of ordinary skill in the art recognize that thetrack may contain more information than the information recited above.

[0029] As noted, the watermark data 201 a and music data 201 bcomprising track 201, although depicted separately in reference numbers201 a and 201 b, are mixed and recorded together on the track. Anenhanced representation of track 201 is shown as track 201 c in FIG. 2.As shown in the representation of track 201 c, the track is divided intoa sequence of track sections 1, 2, . . . , n. (These track sections arealso represented in the depictions of watermark data 201 a and musicdata 201 b.)

[0030] Each track section is a particular length of time, for example,approximately 15 seconds. Thus, if a track is a song that is 3:00minutes long, it may be comprised of twelve 15-second track sections.(Those of ordinary skill in the art will recognize that a track may belonger or shorter than three minutes and that the track sections may belonger or shorter than 15 seconds.) Much of each track section 1, 2, . .. , n is comprised of the mixed music and watermark data. However, eachsection may also include other control and identification data. Inparticular, each of the n sections of track 1 (as well as other tracksand track sections) includes three related data elements: 1) CDID(Compact Disc Identification) or unique identifier which is the same forall sections on a CD (or album), or all other storage medium 2) a tracknumber, and 3) a section identifier (sequence IDs). These data fieldsare described in more detail in above-cited copending application“Protecting Content from Illicit Reproduction by Proof of Existence of aComplete Data Set via Self-Referencing Sections.” Thus, the combinationof track number and sequence IDs for each track section uniquelyidentifies every section on the album.

[0031] The watermark encoded on each track section (having sequence IDs1, 2, . . . , n) of the track 201 b has at least one reserved or specialbit. For example, if there are 50 data bits in the watermark of eachtrack section, the 8th bit may be reserved for the special bit. Thespecial bit is marked (for example, given value “1”) in the first andlast (nth) track section of the track and not marked (for example, givenvalue “0”) in the other track sections 2, 3 . . . , n−1. As noted above,the track of FIG. 2 is formatted by the binder 116 and recorder 114 ofencoder 110 of FIG. 1 and recorded onto medium 130. There may of course,be multiple tracks of like structure recorded. Those of ordinary skillin the art also recognize that the track may be “burned”, transferred,copied or placed on a medium such as a CD by other sources than thoseshown in FIG. 1. In addition, those of ordinary skill in the artrecognize that the watermarks embedded with special bits, sequence IDs,etc. may be in any part of the watermark, such as the CDID or tracknumber. Referring back to FIG. 1 decoder 120 in accordance with thisinvention comprises a renderer 122 and a gate 124 that is controlled byan entirety checker 126 discussed in the above-cited copending U.S.Application “Protecting Content from Illicit Reproduction by Proof ofExistence of a Complete Data Set via Self-Referencing Section.” Renderer122 includes software that checks, for example, whether the special bitis marked in the appropriate sections and other authentication checkingin accordance with the invention, as described further below. Entiretychecker 126 may sample the sections of the CD to determine if otherrandom sections of the album are present and consistent with the trackbeing rendered and, if not, deny rendering. Gate 124 outputs therendered signal, if authorized.

[0032] CD Reader 132 in FIG. 1 is used in the description below torepresent a downloading for rendering of a track that is authorizedunder the SDMI or like protocols. Thus, CD reader 132 may download atrack comprised of track sections 1, 2, . . . , n as shown in FIG. 2 anddescribed above from a CD 130. CD reader 132 may also download forrendering multiple tracks formatted as shown in FIG. 2.

[0033] In a representation of a potential system for unauthorizedcopying, song extractor 142 extracts a song from the medium 130 andcommunicates it to an example CD imitator 144, representative of apossible illicit download of the song via the Internet. The CD imitator144 represents, for example, a software program that providesinformation in response to a conventional CD-read command.Alternatively, the information received from the song extractor can bewritten to a CD medium, and provided to the conventional CD reader 132.

[0034] For purposes of the description, it is assumed that songextractor 142 includes software that attempts to evade the SDMI or likeprotocols. For example, song extractor 142 may convert the trackdownloaded from the medium 130 into a compressed (e.g., MP3) file, whichwill corrupt a fragile watermark. Alternatively, the song extractor 142may attempt to avoid the number of recordings authorized by the protocol(four for SDMI). In this case, the song extractor 142 may downloadindividual track sections of each track and mask each individual tracksection as a separate track or “song” in an associated TOC. If eachtrack section is less than 15 seconds, such importing is authorized byan SDMI system. The CD imitator 144 will place the track sections maskedas separate tracks back-to-back for rendering, thus piecing together theoriginal track as a compilation of 15 seconds masked tracks (i.e., tracksections).

[0035] Referring to FIG. 3, there is a flow chart that illustrates anembodiment of the invention as performed by the software or renderer122, which will prevent such unauthorized rendering. The renderer 122receives a data stream from the CD reader 132 or CD imitator 144. Instep 301, a first (1) section and a last (n) section such as shown inFIG. 2, are identified in the data stream. For example, reader 132utilizes a software-processing portion that recognizes the beginning andend of a track of medium 130 as given in the TOC area of the CD, reader132 selects a track and downloads it to decoder 120.

[0036] The first (1) and last (n) sections of the track may beidentified using the sequence ID number field present in each section,which will identify section 1 and section n, as noted above. In step303, the data for the first and nth sections are decoded and thewatermark data is extracted. The special bits reserved in the watermarkof each of the first and nth section of the track is examined to see ifit is marked in step 305 (for example, have logic level “1”). If notthen rendering is denied, (step 307).

[0037] As described further below, the medium may not have a markedrobust or fragile watermark with at least one special bit on the first(1) and last (n) sections of a track, because (for example), a system(such as the song extractor 142 and CD imitator 144) has re-cast thetrack data in an attempt to reproduce a track in excess of the allottedfour times.

[0038] In step 309, it is determined if the sequence IDs of the tracksections 2, 3, . . . , n−1 interposed between the first (1) and last (n)sections of the track are present and in the correct sequence. If theproper order of sequence IDs interposed between the first (1) and last(n) sections of the track is not found, the rendering is denied in step307. If it is determined that the sequence IDs are interposed betweenthe first and last sections of the track are in the proper order, thenrendering is authorized in step 311. If the track is authorized forrendering, then the track may be played, “burned,” transferred, etc.

[0039] The processing of FIG. 3 may be repeated for subsequent tracksprovided from the medium 130, for example, an entire CD. If anyparticular track of a CD is unauthorized, however, the rendering of anyfurther tracks may be denied.

[0040] Referring back to FIG. 1, if a CD reader 132 supplies a trackthat has the format as shown in FIG. 2, then the renderer 122 will findthe special bits marked on the first and last (nth) track section of thetrack (“yes” in decision block 305 of FIG. 3) and will also find thatthe sequence IDs for track sections 2, 3, . . . , n−1 are in the properorder (“yes” in decision block 309). Thus, the rendering will beauthorized (at least preliminarily) in step 311. It is noted that thedecoder 120 may still deny rendering. For example, if the entiretychecker 126 determines that sections of the watermark have beencorrupted or do not exist (for example, because it is a bootleg or hasbeen recorded more than four times in the SDMI domain), then therendering is denied.

[0041] As noted, the song extractor 142 and CD imitator 144 is used todescribe how the processing of FIG. 3 avoids attempts to thwartunauthorized copying. For example, in the SDMI domain, where the fourrecording maximum has been met, the fragile watermarks will be degradedand will not pass the entirety checker. As noted above, the songextractor 142 may attempt to avoid the number of recordings authorizedby the protocol (four for SDMI). In this case, the song extractor 142may download individual track sections (such as track sections 1, 2, . .. , n in FIG. 2) of each track and mask each individual track section asa separate track or “song” in an associated TOC. If each track sectionis less than 15 seconds, such importing is otherwise authorized by anSDMI compliant system. Once inside the SDMI domain any device includingthe SDMI compliant system will play the tracks in any order. Thus, onecan place the track sections as separate tracks back-to-back forrendering, and thus piece together the original track as a compilationof such track sections.

[0042] However, because each such track section is masked as a separatetrack, the renderer 122 of the invention will process the masked tracksection as a track using the processing of FIG. 3. Thus, for each tracksection masked as a track, it will attempt to find a special bit markedin the first and nth track section of the “track” (i.e., the maskedtrack section) in step 305. For the first track section, it will find aspecial bit in step 305. In general, the renderer will allow a songhaving a single track section and only one bit therein to be rendered asspecial cases of steps 305 and 309, since there may be instances of avery short song (of 15 seconds or less). Thus, the first track sectionwill pass step 305. However, the track sections after the first section(and before the nth section) that are presented as a separate track willfail in step 305, since they will not have a marked special bit. The nthsection, like the first section, will generally pass step 305.

[0043] Thus, because tracks sections 2, 3, . . . , n−1, when masked asseparate tracks, do not advance beyond step 305 before rendering isdenied, unauthorized importing of a track by masking individual tracksections is prevented. At most, only the first and last track sections(that is, the first and last 15 seconds of the song) are rendered. Forall intents and purposes such a pieced together “song” is worthless. Byusing this technique, there is no need for inserting time gaps betweenimported tracks, which, as noted above, may on occasion insert undesiredgaps during authorized rendering and recording of original tracks.

[0044] It is noted that, in the above discussion, the sequence IDs ofthe track being focused on were numbered 1, 2, . . . , n. Where amedium, such as a CD, includes a number of tracks, the sequence ID mayincrease in sequence from the first track section of the first track tothe last track section of the last track. Thus, for example, the firsttrack may have sequence IDs of 1, 2, . . . , n. In that case, the secondtrack will have sequence IDs of n+1, n+2, . . . n+m, where m is thenumber of track sections in the second track. Likewise the third trackwill have sequence IDs that begin with n+m+1, and so on.

[0045] Although illustrative embodiments of the present invention havebeen described herein with reference to the accompanying drawings, it isto be understood that the invention is not limited to those preciseembodiments. For example, the data format of FIG. 2 and the processingof FIG. 3 may be modified, so that the special bit is marked only in thefirst track section of the track (i.e. track section of ref. No. 201C ofFIG. 2). In step 305 of FIG. 3 the processing only looks for the specialbit to be marked on the first track section. While such a format may bevulnerable to attack, more than the above-described embodiment, it maynonetheless provide adequate protection against many types ofunauthorized importing. Alternatively, for example, where the first andlast sections of the tracks both use special bits, using more than onebit may improve control over rendering and thus decrease vulnerabilityto unauthorized copying. For example, the first section of a track maybe marked with two special bits, while the last section is marked withone special bit. The system would then have additional data foridentifying which section was a first section and which is a lastsection in identifying an attempt at unauthorized copying. Thus, it isintended that the scope of the invention is as defined by the scope ofthe appended claims.

[0046] The contents of the following three documents are also herebyincorporated by reference:

[0047] 1) U.S. patent application Ser. No. 09/536,945 entitled“Protecting Content From Illicit Reproduction By Proof Of Existence Of AComplete Data Set Using Security Identifiers” by inventors Michael A.Epstein and Robert M. McDermott, filed Mar. 28, 2000.

[0048] 2) U.S. patent application Ser. No. 09/537,815 entitled“Protecting Content From Illicit Reproduction By Proof Of Existence Of AComplete Data Set” by inventor Michael A. Epstein, filed Mar. 28, 2000.

[0049] 3) U.S. patent application Ser. No. 09/537,079 entitled“Protecting Content From Illicit Reproduction By Proof Of Existence Of AComplete Data Set Via A Linked List” by inventors Antonius A.M. Staringand Michael A. Epstein, filed Mar. 28, 2000.

What is claimed is:
 1. A method for determining the authorization of therendering of a digital recording, the method comprising the steps of: a)identifying a first section and a last section of a track; b) decoding awatermark from the first and last sections of the track; c) determiningif at least one reserved bit is marked in the watermark in each of thefirst and last sections of the track; and d) determining if sequence IDsare interposed in sections between the first and last sections of thetrack in sequential order.
 2. The method of claim 1, including theadditional step of providing at least a preliminary authorization of arendering of the track if the determinations in steps c and d are bothpositive.
 3. The method of claim 2, including the additional step ofdenying a rendering of the track if at least one of the determinationsin steps c and d are negative.
 4. The method of claim 2, whereinsubsequent digital tracks that are authorized are rendered with zerotime gap interposed therebetween.
 5. A method for making a digitalrecording comprised of a track having a number of sections positionedsequentially, including a first track section and a last track section,the method comprising: a) providing a data stream for recording in thetrack; and b) mixing watermark data with the data stream, the watermarkdata having at least one reserved bit corresponding to a position ineach of the track sections, the reserved bit being marked in thewatermark data corresponding to the first track section and the lasttrack section.
 6. The method of claim 5, further comprising the stepsof: c) converting the mixed watermark data and data stream to a digitalform; and d) recording the track in a recording medium.
 7. The method ofclaim 6, wherein the recording medium is a compact disc and the datastream comprises music data.
 8. The method of claim 6, wherein the stepof recording the track in a recording medium includes recording asequence ID in each of the sequential track sections, the sequence IDidentifying the sequential position of the respective track section inthe track.
 9. The method of claim 6, wherein the step of recording thetrack in a recording medium includes recording a sequence ID in each ofthe sequential track sections, the sequence ID identifying thesequential position of the respective track section among a multiplicityof other tracks, each comprised of track sections.
 10. A recordingmedium having at least one track of data including a watermark recordedtherein, the at least one track of data comprised of a number of tracksections, including a first track section and a last track section, thetrack sections having at least one special bit reserved in thewatermark, the special bit being marked in the first track section andthe last track section.
 11. The recording medium of claim 10, whereinthe recording medium is a compact disc.
 12. The recording medium ofclaim 10, wherein each track section of the track includes sequence IDdata that identifies the sequential position of the track section in thetrack.
 13. The recording medium of claim 12, wherein the sequence IDsfor the sequence of tracks sections beginning with the first tracksection and ending with the last track section are 1, 2, . . . , n,where n is the number of track sections in the track.
 14. The recordingmedium of claim 10, wherein each track section of the track includessequence ID data that identifies the sequential position of the of therespective track section among a multiplicity of other tracks, eachcomprised of track sections.
 15. The recording medium of claim 14,wherein the sequence IDs for the sequence of tracks sections beginningwith the first track section and ending with the last track section aren, n+1, . . . , n+m, where n is the sequence ID for the first tracksection and m is the number of track sections in the track.
 16. Therecording medium of claim 10, wherein the track of data comprises musicdata.
 17. The recording medium of claim 16, wherein the track of datacomprises music data and watermark data that is mixed and converted intoa digital form prior to recording the track.